P0341 & P01397 1999 and older
04-21-2015, 06:02 PM
#1
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P0341 & P01397 1999 and older
Confused about the contradicting information posted on the web?
Here is what I found out.
The two camshaft sensors combine their signal output to pin 21 (red/grey) of the 5.2.2 motronics unit.
The output is active low e.g. it pull the nominal 12V of the ECU to ground.
It fires once per camshaft revolution or every other engine revolution.
The two outputs are out of phase allowing the the ECU to figure out which signal is which bank.
Either cam sensor can cause this result as the ECU has no way of determining which is bad if the signal is garbage.
I messed with an intermittent that became solid and then was further complicated when one of the new sensors I bought (not bosch) was bad.
Here is my suggested trouble shooting and what I finally did.
Get to wire bundle in the rear trunk going to the ECU. Unwrap the cloth tape and find the signal wires (red/grey). There is one wire going into the ECU and it is soldered to two wires (one to each sensor) right there close to the ECU in the main wire harness.
Cut them free
Clear your alarms. (between steps constantly)
If you leave everything disconnected it will throw both alarms.
If you connect the bad sensor wire it will throw both alarms.
If you connect the good one it will throw the alarm for the bad one.
1397 is the left side sensor accessible through the inside access panel
0341 is the right side sensor which is under the Oil separator.
Make sure you label the wires to keep from getting confused
The left sensor is easy to get to and change.
The right side sensor is under the AOS which is not that hard to remove from the top with the right rear wheel off. One guy supposedly got the cam sensor off without pulling the AOS but he must of had small hands. and infinite patience. This is a good time to change the AOS anyway.
When you change the sensor measure the signals on the pins. The two outer pins should measure 5V between them and the center signal pin you cut free so you can ohm it back to the lead.
If you have an o'scope or graphing DVM you can clearly see the signals. Remember that the ECU is 12V with no input and that these pull it down to ground for the pulses.
ALSO this is only for the motronics 5.2.2 (99 and earlier) I think that is why there is so much confusion on the web.
I did not start this way and finally broke down and went into the wire harness and solved my problem in 1/2 hour,,, this was after a weekend of changing sensors. When I installed the new sensor that was bad the car starting running like crap. So although it will run with this error if the sensor is sending out garbage it can affect the running
Robert
Here is what I found out.
The two camshaft sensors combine their signal output to pin 21 (red/grey) of the 5.2.2 motronics unit.
The output is active low e.g. it pull the nominal 12V of the ECU to ground.
It fires once per camshaft revolution or every other engine revolution.
The two outputs are out of phase allowing the the ECU to figure out which signal is which bank.
Either cam sensor can cause this result as the ECU has no way of determining which is bad if the signal is garbage.
I messed with an intermittent that became solid and then was further complicated when one of the new sensors I bought (not bosch) was bad.
Here is my suggested trouble shooting and what I finally did.
Get to wire bundle in the rear trunk going to the ECU. Unwrap the cloth tape and find the signal wires (red/grey). There is one wire going into the ECU and it is soldered to two wires (one to each sensor) right there close to the ECU in the main wire harness.
Cut them free
Clear your alarms. (between steps constantly)
If you leave everything disconnected it will throw both alarms.
If you connect the bad sensor wire it will throw both alarms.
If you connect the good one it will throw the alarm for the bad one.
1397 is the left side sensor accessible through the inside access panel
0341 is the right side sensor which is under the Oil separator.
Make sure you label the wires to keep from getting confused
The left sensor is easy to get to and change.
The right side sensor is under the AOS which is not that hard to remove from the top with the right rear wheel off. One guy supposedly got the cam sensor off without pulling the AOS but he must of had small hands. and infinite patience. This is a good time to change the AOS anyway.
When you change the sensor measure the signals on the pins. The two outer pins should measure 5V between them and the center signal pin you cut free so you can ohm it back to the lead.
If you have an o'scope or graphing DVM you can clearly see the signals. Remember that the ECU is 12V with no input and that these pull it down to ground for the pulses.
ALSO this is only for the motronics 5.2.2 (99 and earlier) I think that is why there is so much confusion on the web.
I did not start this way and finally broke down and went into the wire harness and solved my problem in 1/2 hour,,, this was after a weekend of changing sensors. When I installed the new sensor that was bad the car starting running like crap. So although it will run with this error if the sensor is sending out garbage it can affect the running
Robert
05-09-2015, 07:49 PM
#2
I purchased a '99 996 C2 in October 2014. Never been in an accident. Less than 10k miles before I purchased the car, the engine was replaced on the car by the previous owner professionally with a complete rebuild using a '01 block, L&N Engineering Nickies upgrading the bore from 3.4L to 3.6L, forged pistons and their IMS upgrade.
The car runs great but I have the P0341 code and the CEL on. After discussing same with the prior owner, who essentially owned the car for 13 years, it was not on supposedly after the rebuild but perhaps about 5k miles later when it started. The prior owner had the very reputable shop that rebuilt the engine replace the sensors, check and redo the timing, replace the tensioners, etc. and try to trouble shoot the issue to no avail. Even the DME was sent out to be tested and came back just fine. Money was really no object for the prior owner (lucky him).
The master mechanic who did the work tells me the car is running great, nothing is otherwise wrong and I should just enjoy driving it...
I took it to another PCA member recomended Indie for a second opinion. After $1,200 in electrical troublshooting (that was discounted) and sending the DME out again to have it come back good yet again, the only advice given was the possiblity of replacing the entire engine harness---an expensive proposition without a guaranteed result.
I have continued researching the issue and even come across an article stating sometimes, in some models, low battery voltage or a weak starter can even trigger a CPS code.
Porsche's owne OBD II definition of the code for this model is 'Camshaft Position Sensor 1-Signal Implausible, Short to Ground, Short to B+'.
So, it seems to be an electical issue...
I am in South Florida and don't know where you are but if you were able to fix this issue, I am willing to hire you!
Any thoughts/insights would be appreciated.
The car runs great but I have the P0341 code and the CEL on. After discussing same with the prior owner, who essentially owned the car for 13 years, it was not on supposedly after the rebuild but perhaps about 5k miles later when it started. The prior owner had the very reputable shop that rebuilt the engine replace the sensors, check and redo the timing, replace the tensioners, etc. and try to trouble shoot the issue to no avail. Even the DME was sent out to be tested and came back just fine. Money was really no object for the prior owner (lucky him).
The master mechanic who did the work tells me the car is running great, nothing is otherwise wrong and I should just enjoy driving it...
I took it to another PCA member recomended Indie for a second opinion. After $1,200 in electrical troublshooting (that was discounted) and sending the DME out again to have it come back good yet again, the only advice given was the possiblity of replacing the entire engine harness---an expensive proposition without a guaranteed result.
I have continued researching the issue and even come across an article stating sometimes, in some models, low battery voltage or a weak starter can even trigger a CPS code.
Porsche's owne OBD II definition of the code for this model is 'Camshaft Position Sensor 1-Signal Implausible, Short to Ground, Short to B+'.
So, it seems to be an electical issue...
I am in South Florida and don't know where you are but if you were able to fix this issue, I am willing to hire you!
Any thoughts/insights would be appreciated.
05-09-2015, 11:29 PM
#4
Race Director
I purchased a '99 996 C2 in October 2014. Never been in an accident. Less than 10k miles before I purchased the car, the engine was replaced on the car by the previous owner professionally with a complete rebuild using a '01 block, L&N Engineering Nickies upgrading the bore from 3.4L to 3.6L, forged pistons and their IMS upgrade.
The car runs great but I have the P0341 code and the CEL on. After discussing same with the prior owner, who essentially owned the car for 13 years, it was not on supposedly after the rebuild but perhaps about 5k miles later when it started. The prior owner had the very reputable shop that rebuilt the engine replace the sensors, check and redo the timing, replace the tensioners, etc. and try to trouble shoot the issue to no avail. Even the DME was sent out to be tested and came back just fine. Money was really no object for the prior owner (lucky him).
The master mechanic who did the work tells me the car is running great, nothing is otherwise wrong and I should just enjoy driving it...
I took it to another PCA member recomended Indie for a second opinion. After $1,200 in electrical troublshooting (that was discounted) and sending the DME out again to have it come back good yet again, the only advice given was the possiblity of replacing the entire engine harness---an expensive proposition without a guaranteed result.
I have continued researching the issue and even come across an article stating sometimes, in some models, low battery voltage or a weak starter can even trigger a CPS code.
Porsche's owne OBD II definition of the code for this model is 'Camshaft Position Sensor 1-Signal Implausible, Short to Ground, Short to B+'.
So, it seems to be an electical issue...
I am in South Florida and don't know where you are but if you were able to fix this issue, I am willing to hire you!
Any thoughts/insights would be appreciated.
The car runs great but I have the P0341 code and the CEL on. After discussing same with the prior owner, who essentially owned the car for 13 years, it was not on supposedly after the rebuild but perhaps about 5k miles later when it started. The prior owner had the very reputable shop that rebuilt the engine replace the sensors, check and redo the timing, replace the tensioners, etc. and try to trouble shoot the issue to no avail. Even the DME was sent out to be tested and came back just fine. Money was really no object for the prior owner (lucky him).
The master mechanic who did the work tells me the car is running great, nothing is otherwise wrong and I should just enjoy driving it...
I took it to another PCA member recomended Indie for a second opinion. After $1,200 in electrical troublshooting (that was discounted) and sending the DME out again to have it come back good yet again, the only advice given was the possiblity of replacing the entire engine harness---an expensive proposition without a guaranteed result.
I have continued researching the issue and even come across an article stating sometimes, in some models, low battery voltage or a weak starter can even trigger a CPS code.
Porsche's owne OBD II definition of the code for this model is 'Camshaft Position Sensor 1-Signal Implausible, Short to Ground, Short to B+'.
So, it seems to be an electical issue...
I am in South Florida and don't know where you are but if you were able to fix this issue, I am willing to hire you!
Any thoughts/insights would be appreciated.
The connection at the ECU should be checked to, but this requires care and a knowledge that this is a very expensive and delicate electronic controller and any static discharge into it will likely ruin it. However, I suspect the source of the problem is at the engine.
it is probably not possible to manipulate the wiring harness close the connector while the engine is running to see if movement of the harness can trigger the error.
If the CEL is on you can monitor the short term fuel trims and the #1 O2 sensors to see if the engine controller is desperately trying to get the right #2 O2 sensor readings by adjusting the fueling. Probably not as you would probably notice the engine's idle varying or being a bit rougher than usual. This tells you is the ECU recognizes the problem by the sensor readings the timing is not right.
If you have access to the proper Porsche diagnostics computer you (or a tech more likely) could view the cam timing and probably even trigger timing changes at each cam shaft and observe various readings.
That the engine has been apart (more than once if the engine was opened up to check and redo the (cam?) timing) the wheel on the cam that plays a significant role in the sensor's operation could be damaged.